<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <script type="text/javascript" src="../assets/js/vue.js"></script>
    <title>Watch option</title>
</head>
<body>
    <h1>Watch option</h1>
    <hr>
    <div id="app">
        <p>今日温度：{{temperature}}°C</p>
        <p>穿衣建议:{{this.suggestion}}</p>
        <p>
            <button @click="add">添加温度</button>
            <button @click="reduce">减少温度</button>

        </p>
    </div>

    <script type="text/javascript">
        var suggestion=['T恤短袖','夹克长裙','棉衣羽绒服'];
        var app=new Vue({
            el:'#app',
            data:{
                temperature:14,
                suggestion:'夹克长裙'
            },
            methods:{
                add:function(){
                    this.temperature+=5;
                },
                reduce:function(){
                    this.temperature-=5;
                }
            },
            // watch:{
            //     temperature:function(newVal,oldVal){
            //         if(newVal>=26){
            //             this.suggestion=suggestion[0];
            //         }else if(newVal<26 && newVal >=0)
            //         {
            //             this.suggestion=suggestion[1];
            //         }else{
            //             this.suggestion=suggestion[2];
            //         }
            //     }
            // }

        })
        app.$watch('temperature',function(newVal,oldVal){
            if(newVal>=26){
                this.suggestion=suggestion[0];
            }else if(newVal<26 && newVal >=0)
            {
                this.suggestion=suggestion[1];
            }else{
                this.suggestion=suggestion[2];
            }

        })

    </script>
</body>
</html>